This specification covers the material, design, and performance requirements pertinent to the manufacture of commercial forced-air gas-fired (Style 1) and electric (Style 2) combination ovens capable of baking, roasting, rethermalizing, and atmospheric pressure steaming, including low-temperature and bio-steaming. The combination ovens, which may be furnished half-size (Class A) or full-size (Class B), are commonly available in the following types: Type 1—table or countertop units; Type 2—stand mounted units; and Type 3—floor units / roll-in units.